On Sat, Dec 17 2022, Junio C Hamano wrote: > Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > >> So we could invent that as this series currently does with: >> >> git check-attrs --revision <rev> <attr>... <path>... >> >> Or, as I suggested: >> >> git check-attr [<rev>:]<attr>... -- <path>... > > What does <rev>:<attr> really mean? As the syntax for the proposed > feature, I do not think it makes much sense. For example: > > $ git check-attr HEAD:text HEAD^:text -- README.txt > > - With which README.txt are we checking the attribute? The one > taken from HEAD or HEAD^ or the index or the working tree? All of them, but I do think this rightly points out that the "rev before path" part of this doesn't make sense, but shouldn't we be making this work like "git grep" with <rev>/<path> combinations? I.e.: $ git -P grep -m 1 oid HEAD~:cache.h v2.26.0:cache.h v1.6.0:cache.h HEAD~:cache.h:#include "oid-array.h" v2.26.0:cache.h:void git_inflate_init(git_zstream *); v1.6.0:cache.h:static inline void copy_cache_entry(struct cache_entry *dst, struct cache_entry *src) I.e. we currently support: git check-attr [-a | --all | <attr>...] [--] <pathname>... git check-attr --stdin [-z] [-a | --all | <attr>...] So if we add to that: git check-attr --stdin [-z] <rev>:<pathname>... We'd have this do the right thing: $ git check-attr diff -- README.md HEAD:git-send-email.perl v1.6.0:git-send-email.perl README.md: diff: unspecified HEAD:git-send-email.perl: diff: perl v1.6.0:git-send-email.perl: diff: perl Which would technically break backwards compatibility, as we now "support" it (we just interpret the whole thing as a path), but I think such revision-looking paths aren't worth worrying about > - When we say "README.txt has the text attribute", how does the > user tell which "text" applies to the path? From HEAD? From > HEAD^? Regardless of what I'm suggesting here, the "git check-attr" output already has a one-to-one line output correspondance with its input, so just as it does now we'd print both. This looks like a bug though (on master, the missing "\n" is there in the output): $ ./git check-attr diffgit-send-email.perl foo.perl git-send-email.perl foo.perl: diffgit-send-email.perl: unspecified git-send-email.perl: diffgit-send-email.perl: unspecified > - Does the same attribute 'text' have different meaning when coming > from two different tree-ish? Yes, just like "git grep", we'd need to parse & apply the .gitattributes for that revision. Whether we call it "<rev>:<path>", "--revision <rev> <path>" or whatever we'd always want to do that, otherwise what's the point?
